Latero-posterior directed migration of trunk to the concave side of the curve: a biomechanical principle in treating the three dimensional deformity of idiopathic scoliosis with a custom molded high profile TLSO

Semi-structured individual interview, and focus group methodology , were the primary methods of data collection. Detailed descriptions of orthotic treatment, for a specified case example, were obtained from seven experienced spinal orthotists; participants held an average of 16.7 years experience in IS treatment. Sessions were audiotaped, transcribed and data was analyzed using a systematic approach to identify themes. Triangulation of data was completed.

Achieving a “balanced and aligned spine and trunk in all 3 planes” emerged as the primary biomechanical goal for all 7 participants (100%). The orthotists identified specific techniques of the treatment process such as:

• drawing an iliac-clavicle box on the PA x-ray

• determining the location and the degree of forces and finding flexibility of the curve with a hand technique

• reducing lumbar lordosis during casting de-rotating the trunk

• centering the upper torso at the axillas over the pelvis

• creating space on the lateral posterior area of the concave side of curve and the mid-posterior area of the spine

To achieve the biomechanical goal, and re-align the 3-dimentional deformity of IS, orthotists apply de-rotational, anterior, and lateral translational forces on the lateral side of the convex curve, and create space on the side opposite the applied force. These factors result in a biomechanical principle called latero-posterior directed migration of the trunk to the concave side of the curve.

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